Macroscopically detected female genital injury after consensual and non-consensual vaginal penetration: a prospective comparison study.
Lincoln C., Perera R., Jacobs I., Ward A.
OBJECTIVE: The aim of this study was to compare the prevalence, type and pattern of macroscopically detected female genital injury after consensual and non-consensual vaginal penetration to further an understanding of the forensic significance of genital injury in women reporting sexual assault. A secondary aim was to identify any effect of a range of possible variables upon the likelihood of genital injury resulting from vaginal penetrative sexual intercourse. STUDY DESIGN: Two groups of reproductive age women (aged 18-45 years) were prospectively recruited within 72 h of a single episode of vaginal penetrative sex, and macroscopically examined for the presence of bruises, abrasions and lacerations at twelve external and internal genital sites. Forty one women who presented for forensic examination after reporting a sexual assault to police were recruited to the non-consensual group and 81 women who presented for routine cervical screening or with sexual health concerns to a primary health care service to the consensual group. Each group was examined by a different group of doctors, all of whom were experienced in both forensic genital examination and gynaecological examination of healthy and diseased sexually active women. Data collection and examination protocols were the same for both groups. RESULTS: The key finding was a statistically significant difference in genital injury prevalence between women who were vaginally penetrated non-consensually and consensually; 53.7% of the non-consensual group (22/41) and 9.9% of the consensual group (8/81) were found to have at least one genital injury [OR 10.57, CI (4.07, 27.42), p < 0.00001]. Penetration with finger/s and possible pre-existing genital 'infection' were found to be significantly associated with the presence of injury in the univariate analysis after adjusting for consent. Logistic regression demonstrated that women penetrated without consent were 19.5 times more likely to sustain at least one genital injury, than those penetrated consensually [OR 19.53, CI (6.03, 63.24)] and that a penetration scenario that included finger/s was 4.2 times more likely to result in at least one genital injury than penetration without finger involvement [OR 4.25, CI (1.42, 12.78)], when controlling for other variables in the model. Whilst a comparatively low injury prevalence in the consensual group limited interpretation, results revealed possible differences in genital injury typology and pattern resulting from non-consensual and consensual vaginal penetration. Lacerations were seen after both consensual and non-consensual vaginal penetration, while abrasions and bruises were seen exclusively in the non-consensual group. CONCLUSION: This study demonstrated a significant consent group difference in genital injury prevalence and the highest macroscopically detected genital injury prevalence rate resulting from non-consensual vaginal penetration identified to date. Results also indicate that vaginal penetration with finger/s increases the likelihood of sex-related injury. The difference in type of injury sustained as a result of non-consensual and consensual vaginal penetration was an unexpected finding, and warrants further investigation. These results highlight the importance of a standardised means of detecting genital injury based on consistent injury definitions, examination protocols, and examiner experience and suggest that macroscopic genital examination may be uniquely placed to detect consent group differences in injury typology and pattern if they exist.